


The Apprentice of Thanatos

by Amalgamorph, Anxiescape



Series: Legacy of the Underworld [1]
Category: Danny Phantom, Percy Jackson and the Olympians & Related Fandoms - All Media Types, Percy Jackson and the Olympians - Rick Riordan
Genre: Angst, Canonical Character Death, Crossposted on Wattpad and DeviantArt, Family Fluff, Father-Son Relationship, Found Family, Gen, Ghost King Danny Fenton, Hurt/Comfort, Identity Reveal, Mild Gore
Language: English
Status: In-Progress
Published: 2021-02-03
Updated: 2021-03-08
Packaged: 2021-03-14 10:40:42
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 10
Words: 15,664
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29169744
Author URL: https://archiveofourown.org/users/Amalgamorph/pseuds/Amalgamorph, https://archiveofourown.org/users/Anxiescape/pseuds/Anxiescape
Summary: One night after a long day of ghost fighting, Danny meets Thanatos, the Greek god of death. The god tells Danny that he needs the halfa’s help, and offers to make him his apprentice. What could go wrong?Updates on Mondays!
Relationships: Annabeth Chase/Percy Jackson, Danny Fenton & Annabeth Chase, Danny Fenton & Thanatos, Danny Fenton/Sam Manson, Hades/Persephone (Percy Jackson), Nico di Angelo & Danny Fenton
Series: Legacy of the Underworld [1]
Series URL: https://archiveofourown.org/series/2141373
Comments: 78
Kudos: 232





	1. Prologue

**Author's Note:**

> There are not enough Danny Phantom/Percy Jackson crossovers, so we decided to write our own!
> 
> Episodes that take place before this chapter:
> 
> All of season 1 up to just after Maternal Instincts
> 
> This chapter takes place in November of 2007. Danny got his powers August of 2007.
> 
> **We do not own Danny Phantom or Percy Jackson, only the story and our original characters.**

**Notes for the Chapter:**

> This chapter takes place a month before The Titan's Curse.

One late fall evening, Danny was flying around Bar Harbor, Maine, hoping to relax. His parents had decided to take the family to a ghost hunting convention the day after Danny and his mom had returned from their unplanned trip to Colorado. Danny was about to call it a night and head back to the hotel when he heard a scream. He zoomed towards the sound, hoping it was something that he could take care of quickly.

At the source of the call for help, Danny found two young kids, a girl and a boy, cornered by what looked like a large cat. However, it had a snake’s tail and acid was dripping from its fangs. Danny zapped it with an ecto-blast, drawing its attention.

“Leave those kids alone!” Danny called out. The cat-snake hissed at him, spat acid in his direction, and turned its attention back towards the two kids. 

“Please, help us, mister!” the boy whimpered. He couldn’t have been more than ten years old.

Danny never could ignore a plea for help, so he placed himself between the kids and the cat-snake. Danny fired another ecto-blast at the cat-snake, trying to get it to leave. The creature, seeing that Danny was between it and its next meal, snarled at the offending half-ghost, and spat a large glob of acid at them. Danny threw up an ecto-shield and told the kids to run while he dealt with the cat-snake. 

“Where?” the girl asked.

It was only then that Danny realized they were in a dead-end alley. Thinking quickly, Danny told them to grab onto him, stretching a hand behind him. Thankfully, neither child argued with him and grabbed his hand. Danny counted aloud from three to give the kids a warning, then he dropped the shield and took off into the sky, away from the monster.

The girl screamed and the boy whooped with excitement as Danny flew towards a park. Danny landed near a playset and told the two kids that they were safe for now.

“H-h-how did you do that?” the girl asked, holding the boy tightly.

“I’m a ghost.” Danny said like it was the most obvious thing in the world.

The girl paled but the boy just started jumping, asking Danny how many hit points he had and what his attack power was. This confused Danny to no end and the girl exasperatedly told the boy off, “Nico, please leave him alone.” Nico turned towards her, probably to argue back, but he was interrupted by a yowl. Turning around, Danny saw the cat-snake thing stalking towards them.

“Nico!” the girl called, motioning for her brother. Nico ran to her as Danny charged the cat-snake. 

The cat-snake met Danny mid-air, claws out and ready to attack; Danny’s fists were ecto-charged and ready to send this creature back into the Ghost Zone. The cat-snake scratched at Danny, forcing him to dodge. He fired an ecto-ray at the creature, but it barely grazed its flank as it jumped to the side. The cat-snake snarled at Danny and spat more acid in his direction. Danny went intangible, but the acid still hurt as it passed through him.

 _Great, that still hurts no matter what I do._ Danny thought as he shot another ecto-ray at the creature.

Danny and the cat-snake circled each other; the cat-snake snarled and Danny was panting. _How strong is this thing?_ Danny had fought many ghosts in the past few months, ever since he got his powers over the summer; some were humanoid and others were animalistic. Danny wasn’t sure if this creature even counted as a ghost, it didn’t have the characteristic glow of ectoplasm. Danny quickly came up with a plan and put it in action as he was facing the kids. He turned back to the cat-snake and feigned an attack.

The creature pounced and Danny went intangible, forcing the creature to turn and face him again. Before it could pounce again, Danny hit it with a dual ecto-ray at full blast. The cat-snake screeched as it disintegrated into golden dust.

“What just _happened_?” the girl asked, coming out of hiding. Nico stood close behind her.

“I don’t know,” Danny answered, looking down at his hands.

“Is it gone for good?” Nico asked.

“I sure hope so.” Danny turned to face them.

The girl sighed in relief while Nico ran up and hugged him. “Thank you, Mr…”

“Phantom. Danny Phantom.” Danny smiled as Nico ran over to the playset and sat on a swing. He turned back to the girl. “And you’re welcome, …”

“Bianca, and this is my little brother Nico.” She gestured to Nico, who was having the time of his life asking Danny various questions about his stats.

Danny asked Bianca if she and Nico had a place to go, and Bianca said that they did, but she did not seem very happy about it. Bianca called to her brother, saying it was time to go back; Nico reluctantly got off the swing set. Danny asked Bianca if they needed a lift; she looked at Nico, who was having trouble keeping his eyes open, and agreed.

“So, where’s this school of yours?” Danny asked Bianca, who was riding piggyback, while Danny carried Nico in his arms.

“Right there, in the forest.” Bianca pointed to the right.

Danny followed her finger, and found the school. It was a dark and dreary building that looked similar to a prison. _Is this a military school or something?_ Danny thought as he landed behind a tree. Bianca hopped off Danny’s back as he put Nico down on the ground.

“Thank you for the ride, Mr. Phantom.” Bianca said, taking Nico’s hand.

“Will we see you again?” Nico asked.

“I don’t know, Nico. Maybe someday.” Danny said, lifting his feet off the ground. “Well, I need to get going. Goodbye, Bianca and Nico!”

“Goodbye, Danny Phantom!” they chorused as Danny flew back to the hotel his family was staying at.

**Notes for the Chapter:**

> This will be crossposted on:  
> Wattpad: [The Apprentice of Thanatos](https://www.wattpad.com/story/257371316-the-apprentice-of-thanatos)  
> Deviant Art: [Anxiescape: Official Art and Story](https://www.deviantart.com/anxiescape)


	2. Chapter 1: A Godly Encounter

**Notes for the Chapter:**

> This chapter takes place in late January of 2008.
> 
> Takes place between The Titan's Curse and the Battle of the Labyrinth
> 
> Episodes that have happened since last chapter:
> 
> The rest of Season 1; Memory Blank; Doctor’s Disorders; Pirate Radio; Reign Storm; Micro-Management.
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**

Danny emptied the Fenton Thermos into the Ghost Portal for the third time that night. In the space of that evening, the Box Ghost had escaped three times, Skulker twice, and who knows how many of the smaller ghosts. He rubbed his eyes wearily, hoping to at least get _some_ sleep before school tomorrow. As he turned to fly back to his room, a deep voice called his name: “Daniel.”

“What?” Danny turned to face the portal, hoping that he was hearing things. Unfortunately, he was not.

What appeared to be a tall angel with ebony-tinted wings and a black floor-length robe stood on the other side of the open portal. The ‘angel’ had dark skin, long dark hair, and his feathers shimmered with hues of blue, black, and purple. His golden eyes regarded Danny with intrigue. Danny rubbed his own eyes to make sure he was not hallucinating, or dreaming.

“You are very much awake and lucid, Daniel.” The 'angel' stepped through the portal and into the lab, where he towered over the counters and machinery. As he entered the room, a strange feeling washed over Danny; there was a faint tugging at his ghost core, like a fish hook trying to drag him towards the unknown being. Danny shook his head, fighting to clear the feeling.

“Who are you? What do you want?” Ecto-energy started building up in Danny’s hands as he fell into a defensive stance.

The angel raised his hand in a placating manner, and the pulling feeling somewhat diminished. “I mean you no harm, Daniel. I am Thanatos.”

“Wait a minute. Like, the purple dude?” Danny lowered his hands slightly, perplexed.

“No,” Thanatos deadpanned. “I am the Greek god of death.”

“Wow, great, _that’s_ comforting.” Danny scowled and brought his fists back up, the ecto-energy around them glowing a bright toxic green. “Are you here to finish what the portal started?”

“No, Daniel, I am not.”

Now Danny was confused. He lowered his hands. “Then… why are you here?”

“I need your help, Daniel. The spirits of the dead are growing restless and I can no longer handle them all on my own.”

Danny was even more confused now. “Why do you need _my_ help? What can I do? And aren’t you supposed to be a myth, like the other Greek legends?”

Thanatos patiently explained that the Greek myths were very much real; Danny’s jaw fell open at the revelation. Danny asked how it was possible for the Greek myths to still be around and not be seen. Thanatos explained that, through use of a special magic called the Mist, the monsters and many other beings were hidden from most mortal eyes. He told Danny about half-bloods, children with a Greek deity for a parent. Thanatos mentioned a place called Camp Half-Blood, a refuge for those same children to learn how to survive and fight the monsters that hunted them because of their godly genes.

“So, how do I fit into all of this?” Danny asked, still trying to process everything. “How am I supposed to help?”

“You have fought the spirits of what you call the Ghost Zone for many months. I have come to ask for your help in dealing with the ones that have escaped from that realm.”

“Wait, what do you mean, ‘ _escaped_ ’? Who else has gotten out?” Danny felt dread seep into every part of his being. He began to pace frantically across the floor, thoughts about how the ghosts could have escaped without him noticing buzzing frantically around his head. “How did this happen? How could I have not noticed? Did I notice without noticing?”

Thanatos watched Danny pace in confusion. “As the King of the Ghost Zone, I thought you knew.”

Danny froze. “What did you just call me?”

“The King of the Ghost Zone?” Thanatos repeated. “Are you telling me you did not know this?”

“ ** _NO!?!_** " Danny’s voice cracked. “What do you mean I’m the King of the Ghost Zone?!”

“When you defeated Pariah Dark, you became the new King of the Ghost Zone.” Thanatos’ expression turned slightly puzzled. “I find it rather incredible that you defeated the former king two months ago, and you did not know that, by Ghost Zone Law, you succeeded him.”

“Look,” Danny said, his voice dripping with sarcasm. “I’ve been a _little_ busy, okay? There’s always ghosts wreaking havoc all over Amity Park and I’m pretty overwhelmed, like, all of the time. Sorry, but I don’t think I can help you, I just-”

Danny froze and stared at the ceiling as footsteps creaked overhead; somebody was awake. He turned to Thanatos, who just stared at him with the same unreadable expression.

“I’ll just… be right back.” He said quietly. “Don’t… do anything, okay?”

Danny could’ve sworn that he saw a smirk on Thanatos’ face as he turned invisible and flew up through the ceiling to the main floor of the house. He glanced around and grimaced as he saw his dad, Jack, standing in his pajamas in front of the open fridge and chugging out of the milk carton.

“Eck, guess I’m not having cereal tomorrow.” He muttered before flying back downstairs, still invisible.

Thanatos was right where Danny had left him, and his eyes landed on Danny as soon as he phased through the wall. Danny frowned, puzzled.

 _Wait, can he see me even though I’m invisible?_ He thought. To test his theory, Danny drifted across the room, and watched as Thanatos’ gaze followed him. Danny then silently glided up to Thanatos and stopped just a few feet in front of him. He waved his hand animatedly in the god’s face and Thanatos sighed softly.

“Yes, I can still see you, Daniel.” He said, a hint of amusement in his voice.

“Whoa, how can you- wait, no,” Danny shook his head to clear his thoughts as he turned visible again. “Not important right now. My dad’s upstairs and you’ve gotta go, because there is no way I can explain this to him.”

“But there is still very much to discuss, young one,” Thanatos tilted his head. “I have not even told you of-”

“I don’t care!” Danny shouted desperately. “Please, you need to go-”

Danny instinctively turned invisible again as the door to the basement banged open and Jack thudded down the stairs into the lab, an ecto-gun held tightly in his hands.

“WHO’S THERE?” Jack shouted ferociously. He squinted into the darkness of the room. “I know you’re in here, ghostie.”

Danny looked over at Thanatos and gasped, then clamped his hands over his mouth as Jack whipped around to face his direction. Thanatos was still there, clearly visible from the glow of the portal, staring at Jack silently. Danny wildly waved his arms at Thanatos, trying to signal that Jack would see him. Thanatos glanced at Danny from the corner of his eye but made no effort to hide himself as Jack moved slowly towards them.

 _Oh no, oh crap,_ Danny thought. _My dad is gonna see Thanatos and think he’s a ghost and then he’s gonna shoot him, a GREEK GOD, and then Thanatos will KILL him-_

Danny was shocked to see his dad frown, turn around, and stomp back up the stairs. He waited till the basement door slammed shut before he turned visible again and gaped at Thanatos in awe.

“How did you…?” Danny whispered.

“Do you remember the Mist that I mentioned earlier?” Thanatos replied. “You just saw it in action.”

“That is so cool,” Danny sighed. “I wish I could do that, it would make my life a lot easier.”

“Perhaps, in time.” Thanatos said. He turned back towards the portal. “Now, would you like to accompany me to the Underworld? We can converse more without the chance of your father interrupting us.”

Danny didn’t respond; instead, he put his hands to his temples and crouched down low to the floor in an attempt to ground himself. He was absolutely overwhelmed by everything that had happened in the last… hour? Few hours? He didn’t even know what time it was, but he was sure that he was not going to get the sleep that he needed before his math test tomorrow. “I… umm… lemme just-” Danny stuttered. “I honestly… I-I just need some sleep, lemme get back to you on that?”

“Hmm, I have never met a ghost that needed sleep.” Thanatos commented.

“Yeah, well, I’m sure you’ve never met a ghost that had a math test in a few hours, but isn’t this just a day full of new experiences?” Danny quipped.

Thanatos chuckled in response. “Very well, then, Daniel. I’ll see you tomorrow evening.”

And with that, Thanatos walked back through the green mist of the ghost portal, and the doors slid shut behind him.

**Notes for the Chapter:**

> The death boi has arrived!
> 
> Wattpad: The Apprentice of Thanatos
> 
> DA: Anxiescape


	3. Chapter 2: Into The Underworld

**Notes for the Chapter:**

> This chapter takes place the day after the previous chapter, so no more episodes have happened since then.
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**

“Dude, with the way your life is playing out, you could be the main character in a TV show or something.” Tucker said in-between handfuls of chips.

“Yeah, tell me about it.” Danny groaned, facedown in his pillow. It was after school the following day and he, Tucker, and Sam currently occupied Danny’s bedroom. Danny was sprawled out on his bed and Sam sat on his desk while Tucker sat in the desk chair.

“Well, I just cannot _believe_ that you met _Thanatos_!” Sam gushed. “This is just, like, the awesomest thing to have ever happened in your _entire_ half-life!”

“Hey!” Danny lifted his head to scowl at her. “I can be the judge of that for myself, thanks!”

“I mean, she’s kinda right, though.” Tucker stated. “Not everyone gets to meet an immortal being who needs their help.”

Danny didn’t respond. Instead, he looked out the window at the sun, which had begun to set. _Crap,_ Danny thought, sitting up. _It’s time to meet Thanatos._ “Okay, guys, you gotta go.” He said. “It’s time.”

“Have you decided what you’re gonna do?” Sam asked. “Are you gonna help him?”

“I mean, I guess I can give it a try.” Danny conceded. “Maybe I can learn a few things from him. It’s been pretty hard having to learn everything on my own, and he probably knows a ton about ghosts and stuff.”

And with that, Danny rolled off of the bed and gestured to the door. Tucker got up and fist bumped Danny. “Good luck, man.” He smiled.

“Thanks,” Danny sighed.

Sam gave him a quick hug. “Good luck! Tell me everything when you get back, okay?” She grinned eagerly.

“Yeah, I will. Thanks, Sam.” Danny smiled, a light blush dusting his cheeks.

Tucker walked by them, coughing in a way that suspiciously sounded like “Lovebirds.” Sam slugged him in the arm when she caught up with him. Danny sighed and shook his head; would his friends ever change? As Sam and Tucker left, Danny walked down to the living room, where his mom was working on another ghost hunting weapon.

“Hey, Mom. I’ve got a lot of homework due Monday, so I’ll be busy for the rest of the night.” Danny said; Maddie said that was fine and that she would check on him in a little bit.

Danny returned to his room, and moved things around on his desk to make it seem like he had done some homework. Then he arranged his bed to make it look like he was sleeping underneath the covers. With his room ready, Danny transformed and phased down to the lab. Thankfully, Jack was not in there, but Thanatos was. Instead of the long robe from the previous night, he now wore a knee length, one-shouldered, coal-colored chiton (that’s what Sam said the robe was called) with a golden rope cinched around the waist, and bright red leather sandals.

“Umm, hey,” Danny waved awkwardly. He felt the faint tugging at his ghost core again, but it was easier to ignore this time.

“How did your math test go?” Thanatos asked.

“Wow, uhh, I… I mean, as good as it could have, I guess…?” Danny rubbed the back of his neck. “I wasn’t expecting you to ask that, thought you were gonna be all ominous and stuff.”

Thanatos raised an eyebrow. “You said you had a math test today. Now, I am curious as to why a ghost would need to take a math test?”

“Well, I’m not _completely_ a ghost-” Danny paused as he noticed the faint smirk on Thanatos’ face. “Ohh, you’re joking, aren’t you?”

“Mayhaps.” Thanatos’ face was difficult to read, but Danny got the sense that he was amused. Thanatos gestured to the open portal doors. “Shall we go to the Underworld?”

“I mean, sure, I guess.” Danny landed in front of the portal. “After you.”

Danny followed Thanatos through the portal. Thanatos used his wings to fly through the Ghost Zone, which Danny found kind of weird since he was a Greek god; couldn’t he just float around or even teleport them there? They were traveling for a while before Danny noticed that none of his enemies had even attempted to attack him. Danny asked Thanatos about this.

“Most beings, both living and deceased, will not approach me if they can help it.” Thanatos flew around a door to a ghost’s lair while Danny phased through it.

Danny stared at Thanatos’ red sandals and couldn’t stop himself. “Nice shoes, by the way. Why are they bright red? Don’t they kinda clash with the whole gloomy thing you’ve got going on?”

Thanatos turned to Danny and raised an eyebrow. “Are _you_ seriously giving me fashion advice?”

Danny looked down at his own admittedly garish outfit, and conceded the point. From there they continued to their destination in silence. Danny had just begun to wonder how far away the Underworld was when they came to what appeared to be a rough stone wall. Thanatos summoned a scythe and slashed through the ragged rock. Danny watched in amazement as a portal formed in the wall; through the green haze of the portal, Danny saw what looked like an enormous underground cavern. The scythe melted into shadows as Thanatos turned back to Danny.

“Follow and stay close to me,” Thanatos said before flying through.

Danny hesitated a moment before following. He was hit by the frigid drop in temperature as he flew through the portal and he shivered involuntarily; it was even colder than the Ghost Zone. The portal opened onto a dark, rocky ledge. To the right of them was a tunnel burrowed into the cavern wall. To the left lay an enormous chasm. A feeling of dread seemed to waft up from the unknown depths like a foul and pungent scent, and Danny felt fear crawl up his spine as he stared into the void; whatever was down there, he did not want to meet it. Danny lingered for only a moment before hurrying into the tunnel after Thanatos. The feeling of dread lessened its hold on Danny the further he got from the pit, and the tunnel widened until it eventually opened onto a spacious field of black grass. Poplar trees were scattered throughout the field, along with a few blue humanoid wisps that were wandering aimlessly. There was no sky, only dark stalactites and dense mist high above.

Thanatos landed in the grass a few yards from the tunnel entrance, and when Danny landed next to him he was surprised to see that the color seemed to have drained from Thanatos’ entire being. His wings were grayscale, his golden belt was now silver, and his once dazzling red sandals were the color of slate rock. Danny quickly looked down at his own hands, before internally facepalming as he remembered that his own outfit was already black and white. He looked back up at Thanatos, who was now watching him with his still golden eyes.

“What…” Danny’s voice came out in a dry rasp, and he cleared his throat. “What was that? What was in that hole?”

Thanatos was silent for a moment before he answered. “That pit was Tartarus. It is the deepest part of the Underworld, and only the most evil of creatures exist there.” He placed a hand on Danny’s shoulder. “Are you alright, Daniel?”

“Yeah, I’m…” Danny shivered again. “I’m good.”

Thanatos nodded before stepping away and looking out across the vast field at the indistinct blue shapes in the distance. “Alright, we have much to cover tonight. First and foremost,” He turned back to Danny. “We must go and speak with my master, Lord Hades. He has undoubtedly sensed your presence, and I would prefer to explain this to him before he takes a more… drastic action.”

“Drastic action?” Danny grimaced. “I… _really_ don't like the sound of that.”

“I would imagine not.” Thanatos agreed. He spread his wings and pushed off from the ground, launching high into the air as he set off across the plain.

Danny was quick to follow, and he frowned as he flew alongside Thanatos. “So, if you’re the god of death, then what’s Hades the god of?” He questioned.

“Hades is the god of the Underworld.” Thanatos replied. The color slowly returned to his outfit as they distanced themselves from the tunnel. “He rules over the realm and keeps order, while I watch over the souls and spirits and make sure that they go _where_ they are supposed to, _when_ they are supposed to.” He glanced over at Danny meaningfully. “You caused quite a stir down here last year.”

“Last year…?” Danny trailed off as he realized what Thanatos was hinting at; the portal accident. He felt his gut twist. Had he just walked into a trap? He wasn’t meant to exist, was Hades going to fix that and kill him the rest of the way? Maybe he planned to experiment on Danny, or keep him in a cage where all the other gods could see what a freak he was. Danny was quiet as the field sloped up as it passed far below them, and he watched as the few straggling blue wisps grew into a large, rippling crowd. In the distance, he could now see a dark castle rising out of the gloom. “So, did he send you to come get me?” Danny asked quietly. “Cause I’m a freak of nature that shouldn’t exist?”

“No,” Thanatos assured him. “I came to you of my own accord. Daniel, I swear to you, on the River Styx, that no harm shall come to you in this realm, so long as you stay close to me and do not act foolishly.”

A foreboding rumble shook the cavern ceiling above them, and Danny was almost worried that it might cave in. He looked over at Thanatos to ask him what had caused it, but Thanatos was gliding down towards the ground; Danny hurried to follow him. As Danny clued into his surroundings, he noticed what looked like a large turnstile of sorts maybe a mile away from him. On the far side of the large barrier was a black sand beach that ran along a dark, polluted river; on the other side of the river was a dark shroud of mist that covered the land like a blanket. Danny also saw what looked like thousands of people milling about in a large crowd on the beach.

As the crowd approached the turnstile, it funneled into several lines that slowly weaved through the entry stalls until they came through on the other side, where the people either went to a large black-tented pavilion or into the field where they faded into the blue wisps that Danny had seen since they entered the Underworld. The dark palace that Danny had seen earlier loomed ahead to their right. He and Thanatos were only a few yards above the crowd in the field when Danny’s ghost sense began to go off like crazy.

“No way,” Danny said as bluish-white vapor poured out of his mouth. “These are all ghosts?”

“Spirits, yes,” Thanatos watched Danny with a sort of puzzled expression. “Are you alright?”

“Yeah, it’s just my ghost sense,” Danny hiccuped as another cloud of fog wafted out of his mouth. “I’ve never been around _this_ many ghosts before, though.”

Thanatos and Danny landed in front of a two-story tall set of bronze gates that were nestled in a thick obsidian wall which wrapped around the palace. The gates were open wide, and they led into a large courtyard. Danny shuddered when he realized what was pressed into the bronze; the gates were adorned with scenes of death; wars, bombings, natural disasters… Danny decided to turn his attention to what was inside the gates instead.

The inner courtyard was stunning; it was a garden of luminescent flora. Nestled in-between the rare and likely lethal plants were mounds of precious jewels; rubies, sapphires, and diamonds twinkled like stars in the dark soil. In the center of the garden was a small orchard of pomegranate trees. Crystal walkways separated the trees, and multi-colored mushrooms sprouted up amongst the trees’ roots. A bronze fountain stood in the center of the orchard, and a short, dark-haired figure stood in front of the fountain, his back facing the newcomers.

Thanatos knelt when he reached the individual. Danny quickly knelt next to him, not wanting to potentially disrespect someone that he shouldn’t. “Master Nico,” Thanatos said. “It is good to see you.”

When the figure turned, Danny couldn’t stop the gasp that escaped him. He knew this person. The person seemed to recognize Danny as well.

“ _Phantom_? What are you doing here?” Said Nico, someone Danny had not expected to see again.

“ _Nico_?” Danny stood up, shocked. “What are _you_ doing here?”

**Notes for the Chapter:**

> When we were designing Thanatos, we read that his sacred flower is the poppy. So, we thought it would be fun for him to have poppy red shoes to add some color to his outfit.
> 
> _And to be honest, he rocks those red shoes._
> 
> Wattpad: The Apprentice of Thanatos
> 
> DA: Anxiescape


	4. Chapter 3: Death's Apprentice

**Notes for the Chapter:**

> This takes place right after the previous chapter, so no episodes have happened since then.
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**

Nico shrugged awkwardly in response to Danny’s question. “It’s… a long story.” His dark brown eyes seemed to bore into Danny’s bright green ones. “Now, how about you answer my question?”

Danny glanced over at Thanatos. He had risen and was now watching the interaction with a once again unreadable expression. Danny turned back to Nico. “I mean… it’s also a long story. Uhh, Thanatos, here,” Danny faltered, unsure if it was rude of him to not add _Lord_ in front of the god’s name. However, Thanatos took over speaking before Danny could mess up more.

“I have brought Daniel here to meet your father,” He explained. “I plan to take him on as my apprentice.”

Danny stared at the god in surprise; Nico had a similar look on his own face. _Wait, apprentice?! What does that mean? Will I need to leave Amity Park? What about the Ghost Zone?_ Danny’s thoughts were running wild. Danny’s mouth must have fallen open on its own because Thanatos told him to close it. He did.

“Come, Lord Hades is expecting us,” Thanatos bowed to Nico. “It was good seeing you, Master Nico.” He started walking towards the palace entrance.

“We’ll catch up later, okay, Nico?” Danny said.

“Yeah, whatever.” Nico turned back to the fountain.

Danny hurried after Thanatos, who was waiting for him at the entrance. They walked into a large entry hall with glittering obsidian walls and a polished bronze floor.

“You have met Master Nico before.” It was not a question.

Danny nodded, looking at the glittering black stone and statues and everything else, except Thanatos. “Yeah, I met him and his sister in November. What did you mean, back there? You plan to make me your apprentice?” Danny asked.

“Exactly what I said.” Thanatos answered.

“And what does _that_ mean? Being your apprentice? Will it help me with the whole ‘King of the Ghost Zone’ thing?” Danny hoped Thanatos was not like Vlad; Vlad has been trying to get Danny to be his apprentice ever since they met at the college reunion in October, but he wasn’t nearly as nice as the god of death had been so far.

“It means that I will teach you to do what I do, if you wish. And yes, I believe that being my apprentice will help teach you what you may need to rule the Ghost Zone.”

“What do you do? Besides reaping the souls of the dead.” Danny was curious. Reaping the souls of the dead would be cool, but what would that mean for the Ghost Zone ghosts?

“I make sure the dead stay where they belong in the Underworld, I keep the monsters of Tartarus at bay, and I protect the Doors of Me.” Thanatos explained.

Danny chuckled. “The Doors of _what_?”

“You would know them as the Doors of Death, if you studied Greek mythology.” Thanatos stopped in front of an ornate set of doors. “Now, you are about to meet the Lord of the Underworld.” Thanatos gestured at the doors in front of them; they had more pictures like those on the bronze gates out front. “Please, remember your manners, Daniel.” Thanatos warned before opening the doors.

The throne room was massive; there were skeletons wearing different military outfits from different time periods lining the walls. The throne itself seemed to be made of human skulls, making the man on the throne—Danny assumed that it was Hades—seem even more threatening. An overwhelming aura of power and death radiated from the man, and Danny felt the strong urge to hide under a rock and stay there for eternity, but he followed Thanatos as he approached the throne. The closer Danny got to Hades, the more static seemed to fill his mind, making it hard to focus on anything except the man on the throne. It was like he was a puppet, being dragged towards the throne by some unknown power. Thanatos knelt in front of Hades, and Danny quickly followed his lead and kept his eyes on the ground, unsure of what else to do.

Thanatos greeted Hades. “Master.” He stood, but Danny remained kneeling.

“Thanatos,” Hades drawled. “What, pray tell, is this… abomination?”

Danny flinched and glanced at Thanatos, who seemed to be staring icily at the Lord of the Underworld. “This is Daniel Fenton-”

“Uh, Phantom.” Danny mumbled under his breath. Both of the gods stared at him; Danny flushed when he realized they heard him. Looking at Thanatos, Danny could almost hear him say, “Remember your manners, Daniel,” again. Crap. Danny opened his mouth to apologize, but Thanatos continued.

“As I was saying, this is Daniel Fenton-Phantom, King of the Ghost Zone, the half-ghost that has been defending his hometown of Amity Park, Minnesota, for the past four months from the beings that come from the Lost Region of Tartarus.”

“A _half-ghost king_ , how horrid.” Hades sneered. “And why have you brought _it_ into my domain?”

“I wish to take Daniel on as my apprentice.” Thanatos proclaimed.

Hades frowned, and a curious glint filled his eyes. “Why does _Death_ need an apprentice?”

“Things are changing, Lord Hades.” Thanatos said. “Something catastrophic is coming. The spirits of both humans and monsters are becoming unruly, and we will need all of the help we can get. I know you can feel the elder beings stirring.”

Hades stroked his chin, appearing to be deep in thought; Danny worried that he was deciding how to kill him the rest of the way. He glanced up at Thanatos, who motioned for Danny to rise. Hades’ attention turned to Danny as he stood, and his disgusted gaze seemed to turn more thoughtful.

“Do you remember what you did last November?” Hades asked, staring intensely at Danny.

Danny did not expect this question, but answered anyway. “You mean like, my family’s trip to Maine? Yeah, I remember it.”

“Why did you defeat that chimera? You could have left those two children to defend themselves. There was no reason for you to intervene.” Hades had an expression that Danny couldn’t place.

“You mean the cat-snake thing?” Danny asked.

Hades rolled his eyes. “Yes, the _cat-snake thing_. Why did you fight it? You could have been seriously injured, trying to defend those children.”

Danny carefully planned his next words before speaking. “They were in danger, and I had the ability to help them. That’s what I do, I protect people.”

Hades nodded, a glimmer of something in his eye. “Very well, then.” He stood up from his throne and walked closer, shrinking down to a more human size ( _What just happened?_ Danny thought.) “Daniel, Thanatos. Face each other and hold out your right hands. And take off your glove, Daniel.”

Thanatos held out his hand like he was going to shake someone’s hand. Danny pulled off his glove and moved his own hand to take Thanatos’, but a slight shake of the god’s head warned Danny not to; so, Danny held his hand next to Thanatos’, an inch or so of space between their palms.

“Thanatos, god of death, do you accept Daniel Fenton-Phantom, King of The Ghost Zone, as your apprentice?” Hades asked.

“I do.” Thanatos answered. A red and black ribbon wrapped around his hand.

Hades turned to Danny. “Daniel Fenton-Phantom, King of the Ghost Zone, do you accept Thanatos, god of death, as your mentor?”

Danny remembered the conversation they had outside the throne room. “I do.” A green and white ribbon wrapped around his hand.

“Now clasp hands.” Hades instructed. They did and watched as the ribbons wrapped around each other, and up their arms. Danny’s arm felt like it was burning, but with none of the pain. The ribbons stayed for a moment before melting into their skin. “You are now mentor and apprentice.”

**Notes for the Chapter:**

> _Amalgamorph: I have this really cool idea for the apprentice ceremony thing, lemme write it :D_!  
> Anxiescape: *reads it* … Ohh, like the Unbreakable Vow!  
>  _Amalgamorph: … Wait…_  
> 
> 
> Hades doesn’t like Danny very much in the beginning because he is dead and alive, and Hades has never dealt with something like that before; honestly, it creeps him out.
> 
> Thanatos busting into Hades’ throne room with Danny: [Here](https://www.youtube.com/watch?v=KbVEy4ki5yE)
> 
> Wattpad: [The Apprentice of Thanatos](https://www.wattpad.com/story/257371316-the-apprentice-of-thanatos)  
> Deviant Art: [Anxiescape: Official Art and Story](https://www.deviantart.com/anxiescape)
> 
> **New Chapters every Monday!**


	5. Chapter 4: An Underworldly Tour

**Notes for the Chapter:**

> This takes place right after the previous chapter, so no episodes have happened since then.
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**

“So, what happens now?” Danny asked, looking at the glowing silver mark on his forearm. It looked like a word in Ancient Greek written vertically on his arm; unfortunately, Danny did not know Ancient Greek. As he pulled his glove back on, blue-white vapor suddenly poured out of Danny’s mouth. _My ghost sense? Why now? Why not during the weird ceremony? Or when I walked into the room?_ Danny complained internally.

“What was that, _Fenton-Phantom_?” Hades asked.

“It’s my, umm, ghost sense, uh, Lord Hades,” Danny explained nervously. “It allows me to detect when other ghosts are nearby.”

“Hmm,” Hades looked unimpressed. He turned to Thanatos. “You know that you will be busy with everything you do, when will you have time to train your new apprentice?”

“I have a plan. There is no need to worry, Lord Hades.” Thanatos said confidently.

Hades turned back to his throne, waving his hand dismissively. “As long as I do not need to deal with him, do whatever you need to, Thanatos.”

Thanatos nodded and began walking to the door; Danny followed, not risking a final look back at the Lord of the Underworld. The door opened on its own for Thanatos and Danny, and closed behind them. Thanatos started towards the entrance of the palace when a voice called out to him.

“Thanatos! What brings you here?”

Thanatos and Danny turned around to see a beautiful woman in a pale green and gray dress standing by the doors they had just exited. She had dark blonde hair, shimmery gold eyes like the sun shining through the clouds, and a tan like she spent all her days in sunny pastures. As the lady neared, Danny noticed that the gray of her dress was really more of an iridescent silver that shifted into different flower prints and patterns.

“Lady Persephone,” Thanatos greeted. “I am here on some official business.”

“And does this ‘business’ have anything to do with this lovely young man?” Persephone turned to Danny, an expectant smile on her face.

“Yes,” Thanatos answered. “Daniel is now my apprentice.” He held up his arm to show Persephone a mark Danny had not noticed until now. It was silver like his own, but the characters were different.

“ _Fántasma_ ,” Persephone read. She turned to Danny, smiling. “That is an interesting name.”

“It’s, uh, actually Phantom, uh, Lady Persephone.” Danny corrected, blushing slightly in embarrassment. Danny felt Thanatos staring at him again, but Persephone laughed.

“I know it is, Danny. You caused quite the commotion last year.” Persephone said. “I must be off now, but I expect to see you again soon, _Fántasma_.”

She entered the throne room, leaving Danny and his new mentor in the entrance hall. “She’s nice,” Danny commented.

“Indeed, she is.” Thanatos agreed, walking towards the door. “Just make sure not to get on her bad side.”

“Why? What happens then?” Danny walked beside him.

Thanatos glanced at Danny. “Do you know the story of Sisyphus?”

Danny shook his head. “No?”

“Read it, and you will find your answer.” Thanatos said brusquely; he seemed annoyed about the topic, so Danny let it drop for now.

They reached the garden and found Nico sitting on a bench underneath a pomegranate tree. Danny walked over to him; Thanatos waited back on the path. Nico looked up when Danny sat down next to him.

“How did your meeting with Hades go?” Nico asked. “Why does your arm say ‘ _Thánatos_ ’?”

“It does?” Danny looked at his arm, and was surprised to see that his mark was shining through his glove. “I can’t read it, so I’ll take your word for it.”

Nico looked at him, perplexed. “You can’t read it? Aren’t you a half-blood?”

“Well, I’m a half-gh-,” Danny caught himself; he probably shouldn’t be telling his secret to people he barely knew. He decided to try and change the subject, instead. “So, uh, how’s your sister? Bianca, right?”

Nico looked away, and Danny felt anger radiating off him. “She’s dead.”

Danny felt his heart sink. “I’m… sorry to hear that, Nico.” He placed a hand on Nico’s shoulder, but Nico shrugged it off. “Is there anything I can do to help?”

Nico stood. “Unless you know how to raise the dead, don’t bother.” He said coldly before storming off.

Danny watched Nico leave, feeling horrible for upsetting him. He dropped his head into his hands, and remained silent as Thanatos sat down quietly next to him. They sat in silence for several moments before Danny spoke.

“I’m really screwing up today, aren’t I?” He mumbled. “I keep talking when I shouldn’t, and I feel so stupid, but… I didn’t know about Bianca…”

“No one can blame you for being overwhelmed, tonight has been a lot to take in.” Thanatos said comfortingly.

“Yeah, okay, but that doesn’t excuse me being a blunt idiot to Nico. I didn’t…” Danny trailed off.

“And you’re not at fault for not knowing about her death. How do you know Master Nico?” Thanatos asked.

“I met him last fall, in Maine,” Danny sighed. “He and Bianca were being attacked by a stupid cat thing, and I saved ‘em.”

“And have you seen them since?” Thanatos questioned.

“No,” Danny replied. “Honestly, I didn’t think I would ever see either of them again.”

“Then how could you have known that Bianca died?” Thanatos said.

Danny sighed again. “… you’re right…” He glanced at his mark again. “Will this be visible in my human form?”

“I believe so, as it marks you as my apprentice.”

“Great, dunno how I’m gonna explain this to my parents…” Danny said jokingly. He looked back to Thanatos. “So, like, does me being your apprentice give me any special powers?”

Thanatos thought for a moment. “It should grant you strength, and allow you to use powers that only Underworld deities and their children are able to use. You could also use your mark to summon me, or let me know you want to talk.” He stood. “Come now, there is still much to see.”

Thanatos took Danny on a tour of the Underworld, starting with the Fields of Punishment; there were people being chased by large black dogs, running through cacti patches with no clothes on, and other horrible tortures. Danny and Thanatos flew over a large hill where a man was pushing a boulder up the slope, which Danny found to be a rather strange punishment. He turned to ask Thanatos why the man was doing that, but Thanatos sped up and Danny had to hurry after him. While over the Fields, Danny met the three Furies; Alecto, Megaera, and Tisiphone. They couldn’t talk long, something Danny was grateful for; they had claws that looked like they could tear him apart.

Next, Danny saw Elysium. Thanatos told him that was where the heroic and virtuous went when they died; Danny noticed a rather wistful expression on Thanatos’ face, but he felt he shouldn’t say anything. They didn’t enter, but they did fly over the small valley. Elysium looked like those island vacation homes rich people go to. In the center of the valley was a large lake, with three islands in its center. Danny asked about them; Thanatos said that the Isles of the Blest were for those who had chosen rebirth three times and had achieved Elysium three times.

They flew over a large tent next. Thanatos said it was where the souls went to be judged and see if they were worthy of Elysium, Asphodel, or Punishment. The line leading into the tent came from the turnstile he saw earlier. On the other side of the turnstile, Danny saw a humongous dog with three heads.

“Oh my gosh, is that Cerberus?” Danny asked excitedly, pointing to the dog in the distance.

Thanatos looked to where Danny was pointing. “Yes, it is. Would you like to say hello?”

“Yeah!” Danny knew he sounded like a kid on Christmas, but he didn’t care. He wanted to see the big dog!

Thanatos and Danny flew over the turnstile, which looked even more crowded up close. Cerberus stood over the fastest moving line, which walked in-between his legs. They flew around the big dog, getting the attention of one of his heads. It followed them as they came into view of the other two heads. Thanatos approached the middle head, Danny waited a little further away.

“Hey, Cerberus,” Thanatos greeted, petting the middle head. “Have any more half-bloods come through recently?” Cerberus growled in answer, watching Danny with two of his heads; Thanatos noticed. “This is just Daniel, my apprentice.”

Thanatos motioned for Danny to come closer. Danny approached cautiously, being careful to avoid Thanatos’ beating wings; he may like dogs, but he knew better than to intrude in on a dog’s personal space. He learned that rule the hard way when he was about five. Danny held out a hand, letting Cerberus sniff it carefully, waiting for all three heads to take turns. Cerberus seemed uncertain, like he couldn’t decide if he should eat Danny or not. That lasted for only a few seconds before Cerberus barked happily and all three heads started licking Danny.

Danny laughed. He thought that, after Cujo, he knew how to handle big dog kisses; boy, was he wrong! After Cerberus finally stopped licking Danny, he was covered in dog slobber.

“Eww, this is worse than Cujo!” Danny playfully glared at the dog, who barked joyfully in response. Danny sighed happily and pet the middle head.

Thanatos chuckled. “It seems you have made a friend, Daniel.”

“Yeah, kinda noticed.” Danny giggled.

“Unfortunately, you and Cerberus will have to play again at a later time. We need to get going.” Thanatos said, then bid Cerberus farewell. Danny pet the massive dog goodbye, and he and Thanatos left.

Thanatos flew over the river, which he told Danny was the River Styx. There were no spirits on the other side of the water, which Danny found rather odd. Thanatos glanced at Danny and chuckled at how silly and disheveled he looked coated with dog slobber. Danny looked down at himself, and went intangible in an attempt to get rid of the drool; most of the slobber slid right off, but some of it stubbornly stayed put.

“I’m gonna have to take a shower when I get home,” Danny groaned as he shook his hands in an attempt to get the slobber off his gloves. “Where are we going, anyway?”

“I am taking you back home now, Daniel,” Thanatos answered. “You have learned much today, and will need your rest.”

“So, why are we not going back through the Ghost Zone?” Danny asked.

“It is too close to Tartarus. If we attempt to go back through the way we came, it is very possible that you would be pulled into Tartarus itself.” Thanatos explained. “We will instead use the Doors of Me.”

Danny was about to ask what they looked like when Thanatos landed in front of a set of black and silver doors ( _Seriously? How did I miss that?_ ). The doors opened without Thanatos pressing anything, and Thanatos stepped inside what looked like an elevator car. Danny followed, wondering how he did not see the massive doors sooner. He expected it to be cramped inside the elevator car with Thanatos’ wings, but he had no problem fitting in the compartment. The doors closed behind Danny as soon as he was inside.

**Notes for the Chapter:**

> Danny’s not very observant, is he? Maybe that’s why the Observants don’t like him.
> 
> Edit: We changed the glove parts in this chapter and the previous chapter so that Danny took off his glove for the ceremony, because that makes more sense.
> 
> Wattpad: [The Apprentice of Thanatos](https://www.wattpad.com/story/257371316-the-apprentice-of-thanatos)  
> Deviant Art: [Anxiescape: Official Art and Story](https://www.deviantart.com/anxiescape)


	6. Chapter 5: Ad Astra

**Notes for the Chapter:**

> This takes place right after the previous chapter, so no episodes have happened since then.
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**

“So, how do the Doors of _‘You’_ work, anyway?” Danny asked as the elevator moved upwards.

“The Doors are my personal gateway in and out of the Underworld. Both sides of the Doors move after each use, making it near impossible for anyone to find them,” Thanatos explained. “Only I know where both sides of the Doors are located at any time.”

“Will I be able to find the Doors, since I’m your apprentice now?” Danny looked at his mark again. It had faded and was no longer showing through his glove.

“In time.” Thanatos replied.

“Have you ever had an apprentice before me?” Danny was curious.

Thanatos took a moment to answer. “One.” His voice was barely audible.

Danny opened his mouth, but Thanatos cut him off gently before he could ask more. “I do not wish to speak of it, Daniel.”

Danny got the sense that he had upset Thanatos. _Why do I keep messing up today?_ Danny asked himself. Today had just been one screw-up after another. He tried awkwardly to change the subject. “So, why are we in an elevator, anyway? Isn’t this kinda… _modern_ for Ancient Greek stuff?”

“Olympus and its associations follow Western civilization. The interior of the Doors changes whenever the center of Western Civilization changes in order to fit the local culture, and even then it changes with the times,” Thanatos explained. “It wasn’t even an elevator until the 1880s.”

Danny nodded. He and Thanatos stood quietly as the elevator moved. After a couple of minutes, Danny cleared his throat. “Maybe you should add some elevator music, you know? Just to, like, lighten the mood.”

A hint of a smile graced Thanatos’ lips. “I will think about it.”

The Doors opened with a ding. Outside the Doors was a forest that Danny recognized. He flew out of the elevator and up above the trees, and saw a large lake in the distance. “Hey, we’re near Lake Eerie. Cool!”

They flew away from the lake, towards Amity Park. Danny flew in loops and zig-zags, enjoying the open air, while Thanatos flew in a straight line. There were no clouds and a slight breeze; a perfect night for stargazing, or a relaxing flight. Danny watched as Thanatos flapped his wings.

“Why do you flap your wings to fly? Do you actually need them? Can’t you fly using the Mist thing?” Danny asked, flying in a lounged back position.

“I do not think you know how the Mist works, Daniel.” Thanatos stated.

“Correct-a-mundo, my good sir.” Danny replied, flying in lazy circles.

Thanatos shook his head in amusement. “It is good that we start your training tomorrow.”

Danny faltered. “Wait, what? So soon?”

Thanatos nodded. “As I said in the throne room, many ancient beings have been stirring as of late, which is making my job more difficult. Your training needs to begin soon so that you may be able to defend yourself and aid me in the coming war.”

Danny had not considered that since he was now the official apprentice of Thanatos, he would have to take part in something as serious or big as a war. Would he have to fight other cat-snake chimeras again, as well as other Greek monsters? Would he help Thanatos collect the souls of the dead? Or would he have to do something else to help out?

Thanatos seemed to read Danny’s mind. “There is no need to worry about the future, Daniel.”

“But…” Danny began.

Thanatos raised a hand. “Your time to help is not yet, young one. Please do not stress about what your role will be.”

 _Well, how do I_ not _stress over a war that I will_ be _in?_ Danny thought. In the distance, he could see the Ops Center on top of Fenton Works.

“So what time will training start tomorrow?” Danny asked when they landed on the Ops Center.

“I will contact you sometime after sundown.” Thanatos answered. “It will give you some time to explain things to your friends.”

“Wait, you know about Sam and Tucker?” Danny worried that he had gotten his friends in trouble.

“I have kept an eye on you since your accident, Daniel.” Thanatos replied.

“How’d you know about that? Do you have a list of people that are supposed to die or something?” Danny asked, somewhat jokingly.

“Yes, actually, I do have a list. And I had to check it twice because of you.” Thanatos winked. “Now, I believe you still need to clean Cerberus’ slobber off.”

Danny ran a hand through his hair, feeling the stiffness caused by the dried slobber. He sighed and bid Thanatos good night. Before Thanatos left, he warned Danny not to speak the names of any of the gods and monsters, as that might attract their attention. After watching Thanatos fly away, Danny phased down into his bedroom. His desk light was still on and his bed was the way he had left it. He turned the light off as he transformed back into his human form. His alarm clock display read 7:30 P.M.; three hours had passed since he left with Thanatos to visit the Underworld.

Danny grabbed a set of clean clothes from his dresser. He opened his door to go down the hall to the bathroom and take a shower, but he ran into Jazz right outside his room.

“Danny, you’re here!” Jazz said, surprised.

“Yeah, of course I’m here. Where else would I be?” Danny asked, holding the door open with his right hand.

“It’s just that you’ve been so quiet that I thought you had left.” Jazz’s gaze shifted to his arm and her eyes narrowed. “What is that?!”

“What?” Danny followed her gaze. To his right arm. The Greek inscription was black against his pale skin. _Crap._ “This… is _not_ what it looks like, Jazz.”

“Really? Because it looks like you went out and got a tattoo in the past three hours.” Jazz’s hands were on her hips, and a disapproving frown was on her lips.

“It’s not a tattoo, Jazz! It’s just… a permanent marker drawing that I drew cuz… I was… bored.” Danny defended, hoping she would buy it.

Jazz looked into his eyes, trying to stare him down. Danny stood his ground and, after a moment, Jazz backed off, saying that she was going to bed.

Danny sighed, relieved that he had redirected her attention for now. As he walked to the bathroom, Danny wondered what he could do to hide his mark from prying eyes. _I could wear long sleeves, but what would I do in summer? How would I hide it then?_ Danny asked himself.

In the bathroom, Danny saw an ace bandage in the first aid kit above the toilet. _I could wrap my arm with one of those._ He decided, and then stepped into the shower to wash off the dried dog saliva.

**Notes for the Chapter:**

> OwO? A previous apprentice? How intriguing…
> 
> Danny can be smart… sometimes.
> 
> Wattpad: [The Apprentice of Thanatos](https://www.wattpad.com/story/257371316-the-apprentice-of-thanatos)  
> Deviant Art: [Anxiescape: Official Art and Story](https://www.deviantart.com/anxiescape)


	7. Chapter 6: Up In Flames

**Notes for the Chapter:**

> We just couldn’t wait ‘til next week to post this chapter, so here you go!
> 
> This chapter takes place the day after the previous one, so no episodes have happened since then.
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**

Danny called Sam and Tucker after waking up around noon. Both of them wanted to hear about Danny’s night in the Underworld, so the trio decided to meet up at the park that afternoon. When Danny left his house, the January day was bright and chilly. When he got to the park, he saw both Sam and Tucker sitting on a picnic blanket under a tree a ways away from the walking paths that twisted through the dead grass.

“Hey, Danny.” Sam waved him over.

“Hey, guys.” Danny sat down on the edge of the blanket. Sam must have packed the basket because there were a variety of fruits and vegetables that Sam had likely grown herself.

“So, how was your trip?” Sam asked, munching on a large green apple. “Meet anyone interesting?”

“Yeah, did you see Ha-” Tucker began, but Danny slapped his hand over Tucker’s mouth.

“Don’t say his name.” Danny warned, eyes briefly glowing.

“Whoa, Danny, chill.” Sam held her hands up. “What’s your deal?”

Danny quickly removed his hand, feeling slightly ashamed. “Sorry, guys.”

“Sensitive subject?” Tucker guessed, glaring sulkily at the picnic basket—Sam definitely packed it, then.

“No, no, it’s not that,” Danny answered, rubbing his eyes. “I was told not to say the names of any Greek Myth people.”

“Why not?” Sam questioned.

“It could get their attention in a bad way.” Danny answered, grabbing an apple from Sam’s picnic basket and taking a bite.

“What’s wrong with your arm?” Tucker asked Danny, pointing at said appendage.

Danny looked down at his right arm, which was now wrapped in an ace bandage; he had pulled on a hoodie before leaving his house, but the bandage was now peeking out from under the cuff. Danny had wrapped his arm that morning to avoid any questions from his parents. Jazz had raised an eyebrow at him at breakfast, but hadn’t questioned it. “Well,” Danny began. “I should probably tell you what all happened, first.”

Sam and Tucker were enthralled as Danny told them about his adventure in the Underworld. He told them about Cerberus and the Fields of Asphodel. Sam nearly squealed in delight when Danny told her about Persephone’s garden. However, when he got to the ceremony, Danny faltered; he had a feeling that he shouldn’t give out the fact that he was Death’s Apprentice so openly. Instead, he told them that Thanatos wanted to train him to use his ghostly powers so that Danny could better handle the Ghost Zone spirits. He also didn’t mention Nico because he still felt pretty awful about upsetting him.

“Okay, dude, that’s awesome and all,” Tucker said. “But what does that have to do with your arm?”

“There’s… a mark that… let’s me know when they need my help with something.” Danny hated lying to his friends, but he felt it was necessary for a reason he could not explain.

Danny could tell his friends knew he was lying, but they didn’t question him. Sam wanted to see his mark, and Danny decided that it was probably okay to show his friends. It wasn’t like they knew Greek, and even then it just said ‘Thanatos.’

After his friends had studied the mark, Tucker decided that it looked awesome. Sam agreed, but then asked Danny how he planned to hide it; he said he’d just use ace bandages for the time being.

“So what’s the plan, then?” Sam asked, absently bringing a hand to her temple as if she had a headache. “You know, like, with the ‘death god’ and all. When’s he gonna train you?”

“Actually, Thanatos said that he’d contact me sometime after sundown.” Danny said as he rewrapped his arm and pulled on his hoodie.

“You mean, like, the sunset that is currently happening _right now_?” Sam pointed at the sinking sun, eyebrows raised at Danny.

“OH MY GOSH, I GOTTA GO. SEE YOU GUYS LATER.” Danny then leapt up, transformed and flew away from the park and back towards his house.

While in the air, Danny’s mark started tingling with pins and needles. _What the heck_? Danny thought. _Maybe it’s letting me know Thanatos needs me?_ Danny flew intangibly through his bedroom wall and landed on the bed. Not knowing what to do, he waited awkwardly and watched as the sun set through the window. _Wait a minute,_ he thought. _How_ is _Thanatos going to contact me?_

As if answering his question, a rainbow shimmered into view at the foot of his bed. The tingling disappeared as Thanatos’ face appeared in the middle of the rainbow.

“Whoa! That’s so cool,” Danny awed. “What is it?” He reached out a hand to touch the rainbow.

“Don’t touch the Iris Message, Daniel.” Thanatos said quickly.

Danny yanked his hand back. “Why not?” He asked curiously. “What’s an Iris Message? And why was my mark tingling?”

“Interrupting the image is how you break the connection.” Thanatos answered. “And Iris Messages are a way for gods and demigods to communicate with one another. As for the mark, the sensation you felt is how you and I will be able to let us know that the other is trying to communicate.”

“Neato. So, can I use the Iris Message thing, too?” Danny asked.

“I believe that you would be able to, as long as you have the proper payment and a rainbow with Mist available to communicate.”

“Awesome!” Danny gushed. “You’ve gotta show me how to do that sometime!”

Thanatos smiled at Danny’s amazement. “Perhaps another time, Daniel. For now, it is time for your training to commence.”

“Sweet!” Danny said. “So, uhh… where are we gonna train?”

“I have a place set up for us in the Underworld.” Thanatos answered.

Danny asked how he was going to get down there; Thanatos said that he would come and collect him. Thanatos then swiped his hand through the rainbow and his image dissipated. Danny did not have long to wonder how Thanatos would get to him, when he felt a hand land on his shoulder. Danny, still in ghost form, jumped to the ceiling, startled, when he realized Thanatos was in his room. Danny bewilderedly asked the god how he did that.

“That is not important right now, Daniel.” Thanatos’ wings were folded tightly against his back, so as not to take up space in the relatively small room. “We need to start your training.”

“Okay, just gimme a sec.” Danny transformed back into human form and quickly ran out into the hallway and down the stairs.

Danny found his mom and dad working on something in the kitchen. Jack wanted to show Danny what they were working on, but Danny declined and told his parents that he would be studying in his room for the rest of the night. Maddie asked if Danny wanted her to check on him in a little bit.

“Nah, I’ll be fine, just got lots to study for my test on Monday.” Danny replied.

“I thought you just had homework due on Monday.” His mom looked up at him, confused.

“Oh, uhh, yeah, that too. I’m super busy, so don’t disturb me.” He then ran back up the stairs and into his room, where Thanatos was still waiting.

“Ok, I’m ready.” Danny transformed again. “So, how are we getting to the Underworld?”

“We will be shadow-traveling.” Thanatos placed his hand firmly on Danny’s shoulder. “I will need to hold onto you so that you do not get lost.”

“How would I get lost?” Danny wondered aloud.

“I do not exactly know, but I do not wish to find out.” Thanatos answered.

“This sounds… very much not safe.” Danny’s voice was steadier than he felt.

“You will be fine, Daniel.” Thanatos said before they melted into the shadows.

  


Danny’s eyes watered, and it felt like his skin was peeling off his bones; wind roared past him like he was going through a dark tunnel at high speeds. _How fast are we even going?_ Danny wondered. Thankfully the sensation did not last long, though Danny’s eyes were still watering once they arrived in the Underworld.

“That… was different,” Danny said as he looked around. They were in a part of the Underworld that Danny hadn’t seen before, in the center of what appeared to be a large, empty stone arena.

“Indeed it was.” Thanatos agreed. He took a few steps away from Danny and shook out his wings, the feathers ruffling as he stretched his arms above his head.

“So what will we be doing? Are you going to test me to see what I can do?” Danny asked.

“First, we will spar.” Thanatos suddenly lunged at Danny.

“Whoa! What?” Danny yelped as he jumped to the side.

“I need to see what you know and how strong you are, and the only way for me to do that is to spar with you.” Thanatos said as he turned and lunged at Danny again.

“Okay, then.” Danny jumped back. “Come and get me, old man!”

Danny took off flying, hoping to build up some distance between the two of them, but Thanatos made that difficult. He was right on Danny’s tail, trying to grab him. Danny fired a few ecto-rays in Thanatos’ direction, trying to shake him. None of the rays hit their target. 

Danny tried going invisible in an attempt to get away, but had forgotten that Thanatos could still see him. _This is getting annoying,_ Danny thought as Thanatos gained on him. Danny turned so that he was flying backwards and fired more ecto-blasts at Thanatos, none of which landed as Thanatos dodged. _Maybe this will work._ Danny went intangible and flew into the ground. He traveled through the ground to where he thought he was behind Thanatos and flew out to see that the god stood right in front of him with his back facing Danny. _Yes! Now I can get a shot in!_ Danny cheered. His idea had worked; he had gotten Thanatos off his back and now had the advantage.

Danny went to punch Thanatos, but the god whirled around (nearly whacking Danny with his wings) and caught his fist. Thanatos tried punching Danny, but Danny caught his fist in return. They were locked in a struggle. Danny’s boots dug into the ground as Thanatos pushed against his hands to try and knock him off balance. Danny pulled at his ghost core, drawing more power from it in an attempt to push Thanatos back. He could feel his chest growing icy cold, and he suddenly felt a sharp pain as though something had snapped inside his core. The mark on his arm started burning like it was on fire.

Instantly, Danny was engulfed in a burst of green flames. They burned at his skin like acid, and he felt like he was dying in the portal all over again, only this time fire was added to the mix. He screamed in pain as the flames licked at him, burning his gloves off. Danny felt his Lichtenberg scar flare like lightning across his skin again. Through the tears in his eyes, Danny could see Thanatos’ face. His lips moved as if he were speaking, but Danny could not hear him. The green flames had died down and now burned the ground around his feet. Danny hadn’t noticed that Thanatos had backed away from him, but he flinched as he felt the god’s hands grab at his arms.

“ _Voithíste me parakaló…_ ” (‘ _Help me, please…_ ’) Danny whimpered weakly before collapsing in a heap on the ground.

**Notes for the Chapter:**

> See you next week! :)
> 
> Also, let us know if you would like the English translations in italicized parentheses after characters speak in Greek, or if we should just have the phonetic Greek.
> 
> (ALSO, WE DO NOT SPEAK GREEK, WE USE GOOGLE TRANSLATE AND HOPE FOR THE BEST.) (also also, that last part was verified on Google Translate.)
> 
> Wattpad: [The Apprentice of Thanatos](https://www.wattpad.com/story/257371316-the-apprentice-of-thanatos)  
> Deviant Art: [Anxiescape: Official Art and Story](https://www.deviantart.com/anxiescape)


	8. Chapter 7: Τι έχω κάνει

**Notes for the Chapter:**

> This chapter takes place right after the previous one, so no episodes have happened since then.
> 
> Here’s how we’ll format characters speaking Greek in this story:
> 
> If the POV is from a character that understands Greek (eg: Thanatos), then when a character is speaking Greek it will be bolded and have colons in place of quotations, **:like this.:**
> 
> If the POV is from a character that doesn’t understand Greek (eg: Danny), then when a character is speaking Greek it will be spelled with English characters and italicized, with a translation in parentheses afterwards, “ _san aftó_.” _(‘like this.’)_
> 
> If you speak Greek and see that we’ve messed up a translation, please let us know and we’ll try to correct it!
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**
> 
> Chapter title translation: What Have I Done

**Thanatos POV:**

Thanatos stumbled back and watched in horror as his apprentice was engulfed in a ball of green flames. Daniel screamed in pain as the fire burned at his skin. Thanatos was frozen on the spot, feeling as if he couldn’t breathe. This was only supposed to be a simple sparring session. Daniel was not supposed to get hurt. _I cannot lose another apprentice._

Eventually, the green fire died down until it was a flickering flame around Daniel’s feet, leaving Daniel in a strange outfit; he wore a black tunic with a green and silver embroidered hem. Under the tunic Daniel wore a pair of black knee-length leggings, and below that a pair of neon green leather sandals that laced up his calves. A Lichtenberg scar burned white along his left arm, branching across his chest and up his neck. A black laurel wreath sat atop Daniel’s snow white hair. Red blood and green ectoplasm dripped from his nose and mouth and down the front of his tunic. Daniel’s eyes glowed solid green and were full of fear and pain as tears streamed down his face.

“Daniel,” Thanatos stepped forward and raised his hands in a placating manner. “You need to calm down. Please.” He grabbed Daniel’s arms in an effort to calm him, and Daniel looked up at Thanatos, his watery green orbs not quite seeing him.

 **:Help me, please…:** Daniel whimpered. Then his eyes fluttered shut and he fell limply to the ground at Thanatos’ feet.

“Daniel?” Thanatos knelt next to Daniel’s limp form, the green fire flickering and dying out around them. “Daniel, please, wake up.” _Please do not die. Not like Dianthe._

Thanatos gingerly lifted his apprentice up into his arms, and shadow-traveled back to Daniel’s room. Artemis had pulled the moon into the sky while they had been gone. Soft moonlight shone through the window as Thanatos gently placed Daniel on his bed. Thanatos was pulling the blanket over Daniel when the bedroom door creaked open. Daniel’s sister, Jasmine, stood in the doorway; she inhaled sharply, her eyes wide as she took in the scene before her.

“Please, do not shout.” Thanatos pleaded, one hand raised to placate Jasmine. She stared quietly at him for a moment before she released her breath.

“W-who are you? What have you done to Danny?” Jasmine stammered; she had every right to be afraid of him—most mortals were—but Thanatos knew she was more afraid for Daniel than she was for herself.

“I have done nothing to your brother, Jasmine.” Thanatos turned to face her. She took a step back as she shrunk away from him. “He and I were sparring when… something happened.”

“W-why were you two sparring?” She asked.

“I have taken him on as my apprentice. His training began tonight, but I did not expect him to…” Thanatos trailed off, looking at Daniel.

Jasmine looked at her brother, then back at the god. “Are you Thanatos?”

Thanatos stared at her, shocked; how did she know of him? “Yes, I am. How…?”

“I saw your name written on Danny’s arm last night. I looked it up.” Jasmine glanced at her brother again. “Will he be alright?”

“I do not know,” Thanatos answered. “But I cannot stay and watch over him. Will you…?”

“I can watch him.” Jasmine entered the room, closing the door behind her. She pulled the desk chair to the end of the bed. “Go take care of whatever you need to.”

Thanatos nodded his thanks to her and melted into the shadows, leaving his apprentice in the care of his older sister.

  


Thanatos shadow-traveled into Persephone’s garden, under the pomegranate trees. He sat down heavily on a bench, head in his hands. _I cannot lose another, not again. I’m not ready to go through that pain again._ Memories of Dianthe’s death resurfaced, unbidden: Thanatos’ mark disappearing as Dianthe’s life force faded… Dianthe taking her last breath… a village dying as Thanatos took her to the Underworld…

A hand rested lightly on his shoulder, snapping him out of his spiraling thoughts.

“What happened?” It was Persephone, and the usual airy tone was gone from her voice.

“I don’t know. Daniel and I were just sparring when green fire suddenly erupted around him, hurting him, and I couldn’t do anything except watch. His… _screaming_ … it-” Thanatos’ voice cracked, and he looked away from Persephone as emotions welled up inside of him, threatening to overflow.

“Here,” Persephone held out a goblet of nectar. Thanatos made no move to take it from her. “Thanatos, please. You’re injured. Look at your hands.”

Thanatos did, and was surprised to see that angry blisters covered his palms; how had he not noticed his hands were burned? Still, he did not take the goblet. _How can I worry about myself while Daniel is lying in bed, injured, almost dead?_

“Thanatos,” Hades’ voice called. Thanatos turned to see Hades walk briskly up to him and Persephone. “Why do I feel your apprentice trying to join our realm again?”

“What?” Thanatos looked down at his mark; it had started to fade and disintegrate off his arm. “No, no, _no._ Not again.” _Why didn’t I notice?_ He looked up at Hades desperately. “Hades, what do I _do?_ ”

“How should I know? Neither of us are life gods!” Hades sputtered.

Persephone cleared her throat. “Luckily for you two, I am a life _goddess_.” She held the goblet out again. “Take this to Danny. It should help him.”

Thanatos took the goblet this time. “But won’t it burn him up? He’s not a demigod.”

“No, but he is a _descendant_ of a powerful demigod, so he should be fine.” Hades answered. “Now go.”

Thanatos was confused by what Hades had said, but he had more pressing matters on hand as he nodded and shadow-traveled back to Daniel, goblet in hand.

  


Jasmine jumped in surprise when Thanatos appeared at her brother’s bedside. Daniel had changed back to his human form, laurel wreath still in place on his now jet black hair. His Lichtenberg scar was pink against his pale skin, which looked even paler than normal as he lay motionless.

“I don’t know what’s going on with him.” Jasmine sounded like she had been crying. “He looks like… like he’s fading away.”

Thanatos looked at Daniel again. Jasmine was right; Daniel’s life force was slowly fading before his eyes. Thanatos placed the nectar-filled goblet on the desk near Jasmine and quickly stepped away; with how out of control his emotions were at that moment, he didn’t want to risk his power hurting Jasmine. “Give him some of that, only a little for now.”

Jasmine stood and grabbed the goblet of nectar. “What is it?”

“It is called nectar, and it should help Daniel heal.” Thanatos explained as Jasmine propped Daniel’s head up and poured a little of the golden liquid into his mouth. Almost immediately, Daniel’s life force stopped fading and his color improved a little. Jasmine sighed in relief.

“Will Danny be okay now?” Jasmine asked as she placed the goblet on the nightstand and sat on the edge of Daniel’s bed.

Thanatos opened his mouth to answer, but paused as the smell of springtime flowers filled the air. “He will be fine now, Jazz.” Persephone said softly from behind Thanatos.

“Wha-who are you?” Jasmine asked, standing up.

“I am Persephone.” The goddess smiled kindly.

“Why are you here? I-is he going to die?!” Jasmine put her hands to her temples and started hyperventilating; she was working herself up.

Persephone strode forward and enveloped Jasmine in a hug. Jasmine cried into Persephone’s shoulder, her uncertainty about her brother’s survival overwhelming her.

Thanatos stood quietly by Daniel’s bed, watching over his apprentice. He reached for Daniel’s hand, but froze as he remembered Dianthe once again. _I do not wish to be the cause of Daniel’s untimely death._

Persephone spoke softly to Jasmine, who was wiping the tears from her eyes.

“So why have you come here, Lady Persephone?” Thanatos asked.

 **:I have come to make sure you do not do anything rash.:** Persephone said in Ancient Greek, still smiling at Jasmine.

 **:I would not have done anything rash.:** Thanatos muttered.

 **:You did when Dianthe died.:** Persephone’s voice was full of compassion, but Thanatos scowled; he did not want another reminder of his previous apprentice. **:Danny will not die, not today.:**

 **:How do you know that?:** Thanatos asked, sadness creeping its way into his voice.

 **:Look at his life force.:** Thanatos did. Daniel was growing stronger, slowly but surely. Persephone switched back to English. “Now we should leave, and let Jazz take care of her brother.”

Although he did not wish to leave Daniel, Thanatos agreed. They bid Jasmine a good night, and shadow-traveled back to the Underworld.

**Notes for the Chapter:**

> Danny isn’t a half-blood in this story, but we decided that his paternal grandmother was a child of Hades, born before the second world war. Her mother moved from Italy to America while she was pregnant with her. This means that Danny is a legacy of Hades, which Hades didn’t realize until Danny almost died the second time.
> 
> [Danny’s new transformation](https://www.deviantart.com/anxiescape/art/TAoT-Spartan-Form-871130993)
> 
> Wattpad: [The Apprentice of Thanatos](https://www.wattpad.com/story/257371316-the-apprentice-of-thanatos)  
> Deviant Art: [Anxiescape: Official Art and Story](https://www.deviantart.com/anxiescape)


	9. Chapter 8: Explanations

**Notes for the Chapter:**

> This takes place a couple of days after the previous chapter. No episodes have happened since then.
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**

_A cavern ceiling passed high above Danny. He was being carried by someone much bigger than him. He heard crying. Who was crying?_

  


Danny woke up in a strange and gloomy place; it looked like a dark cave. Water dripped from stalactites and onto the rocky ground, forming puddles. Danny was surprised to find that he was not in pain; in fact, he did not feel much of anything as he stood there in the shadows. Danny looked around the cave and saw three old women, staring into the largest puddle in the center of the room. He wasn’t sure why he was seeing this, and he turned when he heard footsteps behind him; it was Thanatos, but he looked different than Danny remembered. His chiton was disheveled and his feathers were dull, as if the color had been drained from them, leaving them almost completely black. There were tear tracks running down the god’s face; he looked grief-stricken.

“Sisters,” Thanatos’ voice cracked as if he had been crying. “You wished to see me?”

The old women looked up at him. Together, they spoke with one voice:

  


_Death shall take a second apprentice_

_Made between the worlds of the Lost and Living_

_Born of pain and sacrifice_

_He shall save all worlds and bring peace to Death_

  


“No, I do not want another apprentice.” Thanatos’ eyes flashed with anger, and something else that Danny could not place. Thanatos stormed out of the cave, and the scene changed.

  


Danny was now in Persephone’s garden. Thanatos and Persephone stood underneath a pomegranate tree; Thanatos’ hands looked burned and his feathers were dark, only a few shades lighter than the previous dream. The two of them were conversing in a different language, but Danny somehow knew what they were saying.

 **:Danny will be fine, Thanatos.:** Persephone gave a comforting smile. **:You know he will.:**

 **:I know, but I am still worried.:** Thanatos’ wings fluttered nervously. **:He nearly died. I nearly lost him, just like I lost Dianthe, and…:**

 _Who’s Dianthe?_ Danny wondered as the scene changed again.

  


Danny now stood in the throne room of Hades’ Palace. Hades sat on his throne and Nico stood in front of him.

“Please, tell me what happened to Phantom.” Nico asked.

“I said that is none of your business, Nico.” Hades sounded like he and Nico had been having the conversation for a while.

“Please, Father. I need to know he’s safe.” Nico’s voice cracked.

Hades sighed. “He is safe enough. Now, leave me.”

Nico bowed and left the throne room. When the door closed, Danny was shrouded in darkness.

  


Pain. That was all Danny felt when he woke up. That and his bed below him. He opened his eyes but quickly shut them again as bright sunlight from his bedroom window shone in his face. He heard movement and flinched as he felt a hand grab his own.

“Daniel,” He heard Thanatos say, relief evident in his voice. “How are you feeling?”

Danny slowly opened his eyes again. The sunlight from his window was now blocked by Thanatos standing over him. The god looked exhausted, but his golden eyes were filled with hope.

“Ni…” Danny coughed. His throat felt like sandpaper. “Nico… is… Hades’ kid?”

Thanatos just stared at Danny. When he spoke, the disbelief was clear in his voice. “… Daniel. You almost _died_ , and _that_ is the first thing that you have to say?”

Danny didn't respond, and instead looked around his room; it still looked the way it had when he left with Thanatos, except for a golden goblet on his nightstand and a chair next to his bed. Based on the sunlight, Danny guessed that some time had passed since their sparring session. “How long was I out?”

Before Thanatos could answer, Danny’s bedroom door swung open and Jazz walked into the room. She was carrying a couple of books, which she dropped when she saw Danny was awake.

“Danny!” Jazz rushed to him and pulled him into a bone-crushing hug. “I was so worried about you! So were Sam and Tucker…”

“Jazz… can’t… breathe…” Danny wheezed. 

Jazz released him, smiling sheepishly. “Sorry. It’s just that… you’ve been unconscious for almost two days.”

“ _WHAT?!_ ” Danny sat up, pain shooting through his chest. “I’ve been asleep for _two days?!_ ”

“Jasmine, may I please speak with Daniel alone?” Thanatos asked.

“Sure, I need to call Sam and Tucker anyways.” Jazz picked up her books and left the room.

“Your sister has been worried about you.” Thanatos sat down on the chair. It creaked under his weight.

Danny glanced over at his mentor. “What happened? I only remember bits and pieces.”

“I don’t understand what happened, myself.” Thanatos answered. “It has never happened… before.”

Danny rubbed at his temples and heard a strange rustling as he did so. He frowned and asked Thanatos what was making that sound. Thanatos told him that, after the fire had died down, Danny’s outfit had changed and a black laurel wreath had appeared on his head. Danny looked at his reflection in the mirror over his dresser. There was a black leaf crown nestled in his hair. Danny was worried that he was now stuck with the wreath in his human form, but Thanatos touched one of the green ribbons that was attached to it and it vanished. Danny got the feeling that it would still be there in his ghost form, though. Then Danny realized something.

“Wait, you and Jazz were in the room together. Were you doing the Mist thing on her?” Danny hoped he could still keep his ghostly identity a secret from his sister.

Thanatos raised an eyebrow. “Daniel, she knows.”

“Oh, crap,” Danny dropped his face into his hands. “… how much does she know?”

“Everything. Samantha and Tucker are also aware that you are my apprentice.” Thanatos spent the next few minutes telling Danny what had happened after he fainted. 

Sam and Tucker had shown up yesterday morning after Danny had not called them to let them know how his training session went. Jazz had tried to get them to leave, but they were persistent in wanting to see Danny. Eventually, Jazz had relented and brought them to Danny’s room. Thanatos had been watching over Danny when they entered. After almost getting hit with a combat boot (courtesy of Sam), Thanatos had explained to them what had happened the previous night. Danny’s friends had then spent the rest of the day watching over Danny before heading home.

As he thought about how to handle his friends now knowing his latest secret, Danny remembered the weird dream he had. “Hey, Thanatos? I have a question.”

“Is it about Nico being a child of Hades?” Thanatos asked with a slight smile.

“No, it’s not that.” _How to put this into words…_ “I had this kinda… dream… vision… thing. About you.”

“Oh?” Thanatos leaned forward.

Danny described his dream as best he could; Thanatos listened with an increasingly somber expression. As Danny went on, he noticed that Thanatos seemed to grow more and more uncomfortable, his wings ruffling and changing shades to reflect his unease. When Danny recited the prophecy, Thanatos grew… well, deathly still. As soon as Danny mentioned the name Dianthe, Thanatos quickly stood and said that he had to go. He promised to return later, picked up the goblet, and melted into the shadows before Danny could say anything else. _Why am I so good at upsetting people?_ Danny thought bitterly.

  


“So, how long have you known?” Danny asked Jazz. The two of them sat alone in Danny’s room, waiting for Sam and Tucker to arrive.

“About you being half-ghost? Since the Spectra thing.” Jazz fidgeted with her sleeve. “How long have you been an apprentice to Thanatos?”

“Since Friday night, I think.” Danny rubbed the back of his neck. “Time’s a bit muddled for me right now.”

They sat in silence, uncertain of what to talk about; Danny still felt like he’d been run over by a flaming steamroller. After a few moments, Jazz spoke up.

“You almost died. The rest of the way, I mean.” Jazz’s voice shook.

“What… what do you mean?” Danny asked.

“Your life force was _literally_ fading.” Jazz hugged herself, as if she was remembering something horrible. “You would have been a goner if Thanatos hadn’t brought the nectar.” Tears started welling up in her eyes.

Danny gently took her hand. “Jazz, I’m fine now.”

Jazz nodded and hugged Danny again, though not as tightly as before. The doorbell rang. Jazz stood and went downstairs. Danny already knew who was at the door before he heard the sound of their feet pounding up the stairs. Sam and Tucker burst into the room; Tucker stood back as Sam ran forward and gave Danny a tight hug.

“Dude, don’t scare us like that again!” Tucker griped as he plopped down on the chair to Danny’s right.

“Yeah, we had enough of that when you half-died.” Sam sat on the left side of the bed. She frowned as she noticed Danny’s discolored complexion. “Your scar. How is it back?” She gently held Danny’s hand, looking at the Lichtenberg scar that was pink against his skin.

“I don’t know.” Sam’s hand was warm and comforting against Danny’s own, so he continued to hold it.

“And where’d the nifty leaf crown go? You had it yesterday.” Tucker was trying, and failing, to hide his smirk.

“It’s still there, I think, just in my ghost form. And it’s called a laurel wreath.” Danny ran his fingers through his hair where the wreath had been.

“Who cares what it’s called?” Sam waved her free hand dismissively, before pointing it sharply at Danny. “Daniel James Fenton, if you _ever_ do that again, I will _personally_ hunt your ectoplasmic butt down, kick it back to Amity Park, and kill you again myself. Ya got it?” Sam’s violet eyes bored into Danny’s blue.

Danny gulped nervously. “Yes, ma’am.”

Once they had all settled down, Danny and his friends talked for several hours. They chatted about lighthearted things such as school, the Ghost Zone, and ghost attacks. Tucker laughed about how he and Sam had been faking ghost attacks to keep Danny’s parents busy so that they wouldn’t grow suspicious of their son’s absence. With the scare that had happened earlier, the trio were content to ignore the elephant in the room: Danny was Death’s Apprentice.

Once the three of them ran out of inane things to talk about, they faded into an uneasy silence. Nobody quite knew how to start the more pressing conversation. Danny wanted to talk about it, but couldn’t find the words. After some deliberation, he spoke.

“So…” Danny began. “Guess you guys know. About the…”

“Apprenticeship?” Tucker supplied. “Yeah. We know.”

“Why couldn’t you just _tell_ us?” Sam asked, the hurt clear in her voice.

“I don’t know why I couldn’t tell you!” Danny said defensively. “I just… felt like I _shouldn’t_.”

“Well, we know now,” Tucker remarked. “So you don’t gotta worry about having to deal with it all on your own. We’re here for you, man.”

“Yeah, we’re here for you, Danny.” Sam agreed, squeezing Danny’s hand reassuringly.

Danny smiled gratefully at his friends. “Thanks, guys.”

**Notes for the Chapter:**

> Like we said, Danny is smart. Sometimes. It just takes him a minute. Also, he’s fine. :)
> 
> Sam has got some guts, just throwing her shoes at the first person she sees. I wonder how Thanatos reacted. As for why Sam, Tucker, and Jazz aren’t super freaked out by Thanatos’ aura, they’re pretty used to the aura of death around Amity Park, as well as Danny.
> 
> Wattpad: [The Apprentice of Thanatos](https://www.wattpad.com/story/257371316-the-apprentice-of-thanatos)  
> Deviant Art: [Anxiescape: Official Art and Story](https://www.deviantart.com/anxiescape)


	10. Chapter 9: Let's Try That Again

**Notes for the Chapter:**

> This takes place a couple of weeks after the previous chapter. No episodes have happened since then.
> 
> **We do not own Danny Phantom or Percy Jackson, only this story and our original characters.**

While Danny was resting for a few days after the weird fire incident, Thanatos had instructed him to start learning Ancient Greek. Sam helped him as much as she could, but she had trouble focusing when she read the Greek characters, and was also busy helping Tucker keep the ghosts at bay while Phantom was out of commission. Danny managed to learn the Greek alphabet in that time, but not how the words and grammar were put together.

When Danny had the energy to go back into his ghost form he found that his suit was back to normal, except for the black and green laurel wreath that now sat atop his head. Danny still had no idea how or why it had shown up in the first place, but it wasn’t bugging him so he didn’t mind.

After Danny had fully recovered a week after the incident, Thanatos took him back to their training arena in the Underworld. They stopped by Hades’ Palace first. Persephone was in her garden when they landed; Nico was nowhere to be seen. Persephone hugged Danny, saying that she was glad he was alright. She made Danny promise not to spontaneously combust again; her intensity reminded Danny of Sam. Persephone then began to speak with Thanatos in what Danny now recognized as Ancient Greek.

While the two of them were conversing, Hades came out to the garden and pulled Danny off to the side. Danny was worried that he had somehow angered Hades, but he was surprised when Hades looked at him with concern.

“I hear you tried joining our realm again, Daniel.” Hades spoke quietly.

“I didn’t mean to, I just…” Danny began, only to be cut off by Hades raising his hand.

“I know, but don’t try again anytime soon.” Hades looked over at his wife and Thanatos talking. “I can’t have one of my descendants die before his time.”

“Wait, what?” But Hades walked off, leaving Danny alone and confused. Danny looked at Thanatos in bewilderment, but Thanatos just waved Danny over to where he stood. Persephone had disappeared while Danny had been occupied with Hades. “Did you hear what Hades said?”

“What did he say?” Thanatos asked.

“He said that I’m one of his descendants!” Danny put his hands to his temples. “What does that _mean?_ ”

“Hmm,” Thanatos put a hand to his chin as if he was pondering Danny’s question, but he had a playful glint in his eye. “I think… it means that you are one of his descendants.”

Danny just stared at Thanatos. “… That’s no help at all, dude. Thanks a lot.”

Thanatos chuckled. “You being a _descendant_ of Hades would mean that one of your grandparents was a _child_ of Hades.”

“ _WHAT?_ ” Danny gaped. “But, bu-”

However, Thanatos was already flying away towards the training arena, and Danny had to hurry after him.

  


Danny trained with Thanatos on and off over the next two months. Mainly, they worked on Danny’s power control and endurance; Thanatos also taught him some more about how the Underworld functioned. Some days, Thanatos was especially busy with his job, so Danny stayed home and worked on learning Ancient Greek.

As time passed, Danny began to think about what had happened at their first training session. _What_ did _happen?_ He wondered. Thanatos had not brought it up since Danny had recovered, and Danny had found the pain a bit too fresh to bring up just yet. However, Danny was now curious; what had caused that explosion, and could he do it again, but not as violently? Danny decided to bring up his thoughts on the event at his next training session, the Saturday before his spring break.

  


Danny stared off into space as he and Thanatos took a break from their latest sparring session. He wasn’t sure how to bring up the subject; however, Thanatos spoke first.

“Is something on your mind, Daniel?” Thanatos prompted.

Danny jumped, startled out of his train of thought. He looked at Thanatos, but then looked away. “Well…” He began. “I kinda wanted to talk about something…”

Thanatos nodded knowingly. “You want to discuss what happened at our first training session.”

Danny stared at him in surprise. “How did you…?”

“I would like to know what happened as well.”

Danny frowned, disappointed. “Oh… I thought you knew…? Like, I thought it was _your_ power that caused whatever that was.”

Thanatos shook his head. “It was your own power that caused it.”

“ _My_ power?” Danny scoffed. “No way, I’m not _that_ powerful.”

“My dear apprentice, you are indeed that powerful. Or have you forgotten that you are the King of the Ghost Zone?” Thanatos stood and shook out his wings, the blues and purples shimmering vibrantly.

“I haven’t forgotten that, I just… haven’t had any time to do anything with it.” Danny stood as well. “I also haven’t had a chance to talk to Sam, Tucker, or Jazz about it.”

Thanatos motioned for Danny to join him. “You will need to do that, but only when you feel that the time is right.”

“When will that be?” Danny asked, standing across from his mentor.

“That, I have no idea. Now,” Thanatos spread his hands in front of him. “I want you to remember how you felt at the time of that first transformation; call on that same power from before, but not as much as last time. I will be here should anything go wrong.”

Danny was understandably nervous. The last time he did this was an accident that had left him unconscious for two days. However, Danny had come to trust Thanatos over the past couple of months, so he saw no reason for Thanatos to lie to him now. Danny closed his eyes, finding it easier to focus on the power he now knew was there, deep within his ghost core. Danny felt the icy cold again, but not the pain. _It’s working,_ Danny thought as he felt the warmth of the fire envelop him, and then leave as quickly as it had appeared.

Danny opened his eyes and looked down at his clothes. They had changed from his usual black and white jumpsuit to a black tunic with a green-and-white embroidered hem and black knee-length leggings. **:Awesome,:** Danny said, before promptly passing out.

  


_Danny sighed. He ran his hands through the long, rainbow-colored grass, gazing over the clear, rippling lake as he did so. The weather was perfect; it always was. He was happy._

_He heard a familiar voice behind him. Turning around, he saw his mother. She called to him again. **:Athos!:**_

  


“-anny?” a soft female voice asked, worried.

Danny groaned and opened his eyes. He had changed back to his human form while he was unconscious. Persephone was leaning over him, and she looked concerned. Thanatos knelt on Danny’s other side. Danny sat up slowly, supported by the worried goddess. “What happened? Did I do it?”

“Yes, you did.” Thanatos sounded proud. “Much more controlled than before.”

“Yes, but you still passed out. You promised not to spontaneously combust again, Daniel.” Persephone scolded.

“Sorry…” Danny felt bad. Then he frowned, confused. “Wait, why are you here? Isn’t it springtime?”

“Yes it is, but I worry about you, Danny.” Persephone stood, brushing her light brown hair back. “I must return to the surface now. I trust you two will be more careful in the future.” Persephone fixed the two of them with a stern stare before she melted into the shadows, going back to her mother, Demeter.

Thanatos offered Danny a hand to help him up, which he gladly accepted. Danny rubbed at his temple, feeling a slight headache.

“Are you feeling alright?” Thanatos asked him.

“Huh?” Danny blinked up at the god. “I…” He… felt like he had forgotten something. “… never mind.” Danny then looked at Thanatos hopefully. “What happened while I was out?” He asked. “Were you able to figure out what’s going on with my powers that causes me to transform like that?”

Thanatos regarded Danny with an intrigued look. “No, I have not figured out what is happening with your powers. However, _échete askísei ta elliniká sas?” (‘Have you been practicing your Greek?’)_

Danny stared blankly at Thanatos. “Uhh… what?”

“Hmm,” Thanatos hummed. “Very interesting, indeed.”

“What are you talking about?” Danny was getting annoyed; what was going on?

“Both of the times that you transformed, Daniel,” Thanatos' voice held a hint of astonishment. “You spoke in Greek.”

“Whoa, what? No way!” Danny’s eyes widened in shock. “How is that even possible? I hardly know English half the time!”

“I do not know, Daniel. As for your new outfit,” Thanatos still looked interested, but his voice now had a solemn undertone. “It appeared rather… Spartan.”

**Notes for the Chapter:**

> Yay! No severe injuries this time! Also, do y’all remember which place has rainbow grass? :)

**Author's Note:**

> We hope you liked this chapter! Please let us know what you think in the comments!
> 
> This will be crossposted on:  
> Wattpad: [The Apprentice of Thanatos](https://www.wattpad.com/story/257371316-the-apprentice-of-thanatos)  
> Deviant Art: [Anxiescape: Official Art and Story](https://www.deviantart.com/anxiescape)


End file.
